Simple Answer – Yes

Yashica Auto Yashinon f/ 1.7 5.8cm lens designed exclusively for Yashica’s Pentamatic II. It appears for the first time in August 1960 and disappears from use by Yashica in January 1961. There’s no documentation about the lens and no hard evidence that Zunow made the lens. Hard evidence would be sales brochures or advertisements that specifically link Yashica and Zunow. Co-branding on the lens ring would have been nice but never happened. Unfortunately our claim that it was made by Zunow is, at this point in time, circumstantial and coincidental. Much more digging around needs to be done on our part.

The lens features the unique Pentamatic bayonet mount that couldn’t be used on any other SLR of the time without an adapter. That in and of itself could have been a major reason for the quick demise of the Pentamatic series of cameras.

Two “clues” that link this lens to Zunow – the serial number style with its unique “No xxxxxx” vice the more typical serial number style that Tomioka used “No. xxxxxxxx” at the time (as did most lens makers). Another clue, the style of the lowercase “a” in Japan. Most Zunow lenses used a fat “a” vice the keyboard style lowercase “a”. We know, these are hardly the type of clues needed to link the two but they’re good ones for now.

Could the f/ 1.7 5.8cm lens have been made by Tomioka Optical? Of course, Tomioka was the almost exclusive lens supplier to Yashica since the beginnings of Yashica in 1953. We feel that Tomioka had their hands full making nearly 1,500 lenses per month for Yashica’s first Pentamatic model (which was still very much in production at the time), and then taking on this lens at about 1,000 lenses per month for the Pentamatic II may have been a bit much for Tomioka.

This lens is so radically different in design and function of other Tomioka made SLR lenses of the time (Tomioka only started making lenses for an SLR in September 1959 with no known examples found before that).

Here’s a peek inside of this lens –

It features quality construction throughout and what we feel is another Zunow cue, 10 aperture blades. The Tomioka f/ 1.8 5.5cm lens for the original Pentamatic has only 6 blades. We’ve yet to take one apart (soon).

Pictured above is the f/ 1.7 5.8 Pentamatic II lens with its 10 aperture blades. Below, the front lens group removed from the lens barrel.

Original sales brochure (below) dated February 1961 featuring the Pentamatic II and its very unique lens.

Is All of This Enough to Prove a Connection to Zunow?

No of course not. Our claim is a merely a starting point for further discussions and discoveries. We hope to disassemble the Tomioka f/ 1.8 5.5cm lens that was made for the first Pentamatic and compare it to this f/ 1.7 5.8cm lens for the Pentamatic II. By the way, the Pentamatic II was only available for sale in the domestic markets in Japan. There’s no evidence that it was ever exported. We do know that Zunow Optical and Yashica did have a working relationship by the mid 1950s with Zunow supplying high quality D mount cine lenses for Yashica’s 8mm movie cameras (see below).

Thanks for your visit! Comments are always welcome and your input is important to us. This post is designed to stimulate discussion as to the validity of our assertions. Heck, we may have missed significant clues along the way that would either prove or disprove our claim.

By the way. A special shout out to my good friend and fellow Yashicaphile, Paul Sokk! Our frequent correspondence on this subject first planted the seed that this lens could have been made by Zunow. Paul rightly reminded me that the bankruptcy of Zunow in January 1961 coincided with Yashica stopping production of the Pentamatic II. Yashica is thought to have acquired Zunow after that and one would assume all of Zunow’s assets and debts.

Chris

Be sure to stop by our online store CC’s Studio Twenty-3 Eighty at https://www.ccstudio2380.com for some neat items of photographic interest! Thanks, C&C